The prior art teaches that heat generated by a spooled tether cable for an underwater vehicle must be conducted to the exterior of the drum where the heat is then dissipated. The cable jacket material, winding tension, and the exact positioning of the cable on the drum serves to trap fluid around the cable. Therefore, the prior art teaches that fluid surrounding the drum only impacts the exterior of the drum and that fluid trapped between spooled cable segments is substantially static and of nominal value in cooling the spooled cable.